Three types of taxonomic studies have been made of Japanese ostracods. The first of these are studies which have treated particular taxa, trying to contribute to taxonomic knowledge. The second has been concerned with the description of, or synecological treatment of, local faunas. And the third has focused attention on the application of paleontology to geological age determination. The last two lines of study have usually been accompanied by descriptions of species to ensure proper identification, but these are often far from ideal from the standpoint of taxonomy.

In fact, many of the Japanese ostracods have been described by authors who did not pay sufficient attention to what extent a taxon should be described and to which characters taxonomic weight should be assigned. Some of the existing confusion in Japanese ostracod classification, especially at the species level (as exemplified by the species of Japanese Bairdia, Loxoconcha and Aurila), seems to originate from this early attitude of Japanese taxonomists. "Accurate synonymy is a sine qua non" (Neale, 1964, p. 258) not only for the ecology and biogeography of ostracods, as emphasized by Neale, but for all branches of evolutionary biology. Confusion at the generic level of classification may also originate in a spurious choice of identifying characters for the genus. An example can be seen in Cytherura, Semicytherura, and some allied genera, in which the characters chosen by the original authors to separate these genera seem no longer to serve as diagnostic criteria; the morphologic gap in these characters does not correspond to a phylogenetic gap between the taxa. Because of the polythetic aspect of many cytheracean genera, taxonomic evaluation of characters based on phyletic weighting would seem advisable for genus and family group classification. For an ex ample of such an evaluation and its application to the classification of some Japanese cytheraceans, see Hanai (1961, 1970).

The most recent checklist of Japanese ostracods was prepared by Hanai in 1959; in it he reviewed the history of studies on Japanese ostracods giving a list of 65 species, Since then, our knowledge of both fossil and living species has expanded rapidly. The number of ostracods from Japan and its adjacent seas described up to the end of 1975 totals 366 species. This enormous increase of known species during the last 15 years indicates advances in taxonomic studies of Japanese ostracods. However, it may also signal severe problems. We may be producing "a growing mass of dry-as-duat" (Carr, 1961, p. 9) specific names. Taxonomic revisions are now needed to put some of these nominal species in order, before a situation is reached whereby subsequent workers unavoidably expend much of their time in locating type specimens and out-of-print publications in order to make identifications. Further, it is hoped that the kind of compilation offered here may provide guidance and suggestions for future studies.